package org.hot100_1;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class leetcode6 {
    public static List<List<Integer>> threeSum(int[] nums) {
        List<List<Integer>> res= new ArrayList<>();
        Arrays.sort(nums);

        for (int i = 0; i < nums.length; i++) {
            if (nums[i]>0){
                break;
            }
            //对i进行去重
            if (i>0 && nums[i]==nums[i-1]){
                continue;
            }

            //开始查找三元数
            int left =i+1;
            int right =nums.length-1;
            while (left<right){
                int sum = nums[i]+nums[left]+nums[right];
                if (sum>0){
                    right--;
                }else if (sum<0){
                    left++;
                }else {
                    List<Integer> list = new ArrayList<>();
                    list.add(nums[i]);
                    list.add(nums[left]);
                    list.add(nums[right]);
                    res.add(list);

                    while (left<right && nums[left]==nums[left+1]){
                        left++;
                    }

                    while (left<right && nums[right]==nums[right-1]){
                        right--;
                    }

                    left++;
                    right--;
                }
            }
        }

        return res;
    }

    public static void main(String[] args) {
        int [] array ={-1,0,1,2,-1,-4};
        List<List<Integer>> lists = threeSum(array);
        System.out.println(lists);
    }
}
